Resonance phenomena, which may cause vibrations of the drive train of a machine, such as a helicopter, may be engendered by the coupling of the natural modes of the drive train to those of the fuselage through the variation of the rotor speed and the yawing motion of the fuselage. The vibrations may in turn render the overall machine unstable or difficult to control. It is therefore desirable to damp such a resonance of the drive train.
Various methods may be used for increasing the damping of the rotor resonance. Resonance damping may for instance result from the aerodynamic drag on the rotor blades, gear reductions, and inherent losses in the system. However, such damping may not be sufficient and additional damping may be desirable. For this purpose, control systems, which increase the resonance damping, may be used. However, such systems are typically complex and require high computational power.
There is therefore a need for an improved system and method for damping a resonant mode of a rotor drive train.